Well I think it's pretty, and pretty silly.
Pat Cullinan Jr: <quote>should provide the depth-of-field control and low-light image quality on an APS-C DSLR that you'd get using an F2.8 zoom on 35mm full-frame.</quote>
The aperture of a lens is quite independent of the format of the film or sensor. In other words, f/1.8 is f/1.8 whether the lens is placed before an APS-C sensor or a full-frame sensor. The intensity of the light striking the target is the same whether you have a small or a large target. The aperture is a function solely of the focal length and the entrance "pupil" (meaning the diameter of the circle of light you see when you look through the lens from the rear).
I hope everybody understands this, because otherwise you'll be making disadvantageous decisions or doing things wrong.
Yada, yada, yada. Of course it is a faster lens, but truly equivalent as it allows the DX shooter to shoot at an ISO just over one stop lower.
jtan163: I think I'd like one, especially for low light (would've liked to have seen some low light/night shots), but I'm not sure I can justify it.
I wonder if they'll try something in a focal length range in the short to mid tele range.
Either way it's a pretty nice time to be a photographer/camera buff/geardo.
As a DX proponent, I like the concept. I'm thinking this lens might really cook with a D7100. However, as I'm mostly a wildlife shooter I think my 17-50 f2.8 Tamron screwdriver may be "good enough".